Coalbed methane: A review

The commercial extraction of methane from coal beds is now well established in a number of countries throughout the world, including the USA, Australia, China, India and Canada. Because coal is almost pure carbon, its reservoir character is fundamentally different to conventional gas plays. Coalbed methane (CBM) forms as either biogenically- or thermogenically-derived gas. The former occurs in ‘under mature’ (< 0.5% vitrinite reflectance) coals...